Hello, I'm not sure if Bugs is the right forum for this, but I don't know where else it would go.
As it stands now there is no set time limit for custom sound effects in the game, which are very easy to create for yourself. If you wanted to, you could, say, create a 30 second countdown sound effect for when mega health expires, so you would know exactly when it spawns due to the custom sound cue. I don't know if any players abuse this, but it probably needs to be addressed.
Current version 1.0.4